A battery post terminal is fixed to a battery post projecting from an upper surface of a battery mounted on a vehicle such as an automobile, and harnesses for power supply are connected to the battery post terminal. As a structure of fixing the battery post terminal to the battery post, there is one in which side surfaces of the projecting battery post are sandwiched, a bolt is inserted from a lateral direction and fastened to be fixed. However, in the structure in which the bolt is fastened from the lateral direction, it is sometimes difficult to perform the fastening work in an engine room with a large number of parts. Accordingly, a structure capable of making a bolt to be inserted from an up-and-down direction and fastening and fixing the bolt at an upper side of a battery post terminal, is proposed (refer to Patent Documents 1 and 2, for example).
Meanwhile, in recent years, there is a tendency that an electrical component such as a navigation device, electronic control devices of an engine, and the like are added, and a load with respect to a battery becomes large. Further, in order to deal with recent environmental problems, a number of vehicles provided with an idling stop function is also increasing. For this reason, a problem caused by a reduction in a charging rate of a battery is concerned, and it is desired to install a battery status detecting device which monitors a status of the battery. A detection sensor of the battery status detecting device is attached to a battery post terminal.